Drill bit or auger



I H. DOSIMONT DRILL BIT on Aue'pn Filed April 13. 1921 F Inventor,-

Patented Feb. 12, 1924.

res-

PATENT SOOIETE ANONYME, OF BRUSSELS, BELGIUM, A CORPORATION.

DRILL BIT on AUG-En.

Application filed April 13, 1921. Serial No. 461,050.

To all whom it may concern e 7 Be itknown that I, HENRI DosIMoN'r, a subject of the King of Belgium, residing at Arville, Province du Luxembourg, in the Kingdom of Belgium, have invented certain new and useful Improvements in Drill Bits or Angers, of which the following is a specification.

This invention relates to drill bits or augers used for boring wood.

In bits designed for the boring of the holes of considerable depth, the body of the bit has heretofore usually been composed of a rod or flat bar twisted hellically and designed to act as a lateral guide for the bit and to prevent its oscillation in the hole bored. "It has already been proposed, in connection with bits or angers of this type, to form at the end of the spirally-wound bar or 'rod' a head with an unbroken periphery designed to facilitate still further the guidance of the bit, the said head being perforated with passages for permitting of the escape of the shavings cut by the bit properly so called. i

- In all the known constructions the disadvantage, however, is met with that, during drilling at considerable depth, the shavings cut off accumulate in the turns of the spiral formed by the twisted rod serving as a support to the bit, with the result that it is necessary, frequently to withdraw the bit from the hole in order to permit of the removal of the accumulated shavings, which would otherwise render the boring operation impossible. I

This disadvantage arises from the fact that, in all existing constructions of bitor anger, the separated shavingsare forced by pressurebetween the spirals formed by the twisted bar of the bit, each fresh shaving cut off forcing in front of it those previously severed; the result is that the shavings accumulate gradually in the spiral and press against the walls of the hole which is being bored and wedge themselves therein, and eventually completely stop up one or more of the spirals of the bit.

This invention has mainly for its object to obviate this particularly important disadvantage and to obtain an automatic evacuation of the shavings without the liability of any stoppage taking place which would necessitate a withdrawal of the bit during the boring operation. I

This result is obtained, accordingto the invention,by making the body of the bit, instead of from a simple rod or. bar helically twisted, as hitherto, in the form of a feed device, the body of the bit being composed of a rod of cylindrical section, in which is cut, for example, throughout its whole length, a feed-helix.

Furthermore, in the practical realization of the invention, as the feed-helix is cut or formed in a rod of cylindrical section,.it is possible to give the spirals any desired depth,whereby the external peripheral surface of the helix can perform the role of a guide surface replacing, underzparticularly advantageous conditions, the guidance hitherto obtained by the twisting of the bar forming the body of the bit.

The bit forming the subject of this invention is, therefore, distinguished from bits the bodies of which are formed from a strip or bar. twisted to a helical shape, by reason of the fact that each turn presents two surfaces which serve a predetermined purpose, one ofthese surfaces being substantially perpendicular to the longitudinal axis of the bit and the other-being an external peripheral surface enveloping the longitudinal axis and constituting the guide surface in the hole bored. e

The improved bit, or anger is preferably provided, in a known manner, with a solid head forming a lower guide surface, and this head is provided with evacuation passages which possess the peculiarity of forming a continuation of the helicoidal discharge passage in such a manner as to effect the discharge of the shavings over a surface corresponding to the inclined dis,- charge passage, which comprises the characteristic feature of the invention. Furthermore, the bit' is characterised by the fact that it is provided, in planes perpendicular to the axis, with two or more spoonshaped cutters "formed by the orifices'of the discharge passages. for the shavings at the end of the bit. I This construction eflects F l'glll'fl 3 is a sectionali view of the .head

ofrthe, bit taken. substantially. along the line AB of Fig. 2 and showing, the arrangement ofthe discharge passages Figures 4, 5, 6, and 7 are views of the lower portion. of the bit in, various positions ofrotation.

shown. in Fig. l, the bit or auger forming the subject of the, invention instead .of be'ing made, as has, hitherto een the practiceefrom a flat-bar twisted to a helical form, is composedof a cylindrical rodla v the original diameter of whichlcorresponds to thediameter of, the head 6, which. determines the diameter of the bit. This rodgasis cut in such-annanner as to provide, dischargehelix c, the pitch d of which is equal to the diameter. The cutting, of the helix. is, moreover, so carried out that each spiral presents What may be termed a discharge surface f coiled around the core a and: a peripheral guide surface ,9 of a suitable depth and design for ensuring the eflicient guidance of the bitlinzthe hole bored.

By reasonof the factxthat the pitch d of the helix is-equal tothe diameter eiof the head of the bit, theinclination of the discharge surface fis such that during. the rotation of the bit in. the hole bored the shavings located between two successive spirals are discharged by therotation of the bit Without any pressure being exerted inthe axial direction other than that resulting from the combined action of the helicoidal surface 7 andof the wall of the hole. The result of'this arrangement is that, if the bit turns without boring, it completelyemptiesthe hole bored of an shavings which may. be found there. The head if thebit shownris of unbroken peripheryfand the discharge surface 7 of the helix xteiids into thesolid, head Z) .in the form of one or more passages h, which pessess thelsame-inclination and open into the r-face, ibff the bit, ashspoonshaped recesses, formin-gg cuttersi In; the example illustrated; it is assumed that -Y the head b isi p rovided with two spoon shapedl cutters j, j situagteclin slightly different planes, that isfa t di fie'rent distances from the tip of the bit, each of the said cutters corresponding to a passage h, M, forming a prolongation or extension of the helicoidal discharge surface 7. The bit is terminated by a screw point it which however is not indispensable but which may be useful for the purpose of centering and for facility in work.

It willbe noted that, as a result of the arrangement of the two cutters j, y in two different planes perpendicular to the axis of the bit at levels slightly different from one another, the action of the bit is progressive, each ofthe cutters j, only cutting the wood over a width corresponding to a. quarter ofthe diameter of the bit, Thus the cndlface of the bit is provided with the vcentral screw point and two con,- centrically arranged helical extensions which terminate in cutting shoulders at different distances from the end ofthescrew point, the; inner extension terminating nearest the tip of the screw. The apertures h and [0. emerge through the extensions at theirterminals so as to form 1 the cutting edges at the terminals of the extensions.

The cutting edges also extend along the outer edge of the terminal so thatthe advance terminal of each extension cuts, a.

corner. The shavings. thus, produced, ,by reason, of the inclination of the-passages h, 71 forming the extension: of the-helicoidal surface 7, substantially enter into. the, dis-, chargescrew without being pressed against oneanotherxasis the casewith hits as heretofore made, and these shavings are immediately. automatically evacuated,by. the discharge surface f withoutany liabilityof the bit becoming clogged up; holes,fi therefore, can-be bored ofv any, depth iii-any kind of wood and at any desired speed. without the liability of the occurrence of any of the well-known disadvantages which are. met with in the use of bits as heretoforevmade;

hat I claim is:

1. Ina bit or auger, a body: formed of a cylindrical rod provided with a,helical groove, a head at the end of said rod, the said head having an unbroken periphery and passages forming cutting orifices in said head, the said passages being formed as extensions ofthe helical groove, and

y ending in the face of theheadperpendic ularly to the longitudinal axisof, the-rod,

2. In a bit or auger, abody formedgof-a cylindricalrod, the said rodbeing. prov ded with a helical groove, theipitch; of which corresponds to the diameterof the,cylinjolrical rod, the-external peripheral surfaceg'of the rod forming ahguiding surfacerfor the bit in the hole formed, ahead at the end ofsaidrod, the-said head being provided with two cutters placed at different-levels andiendin in, two planessperpendicular to the axis of the bit, the said cutters oo- III operating with discharge orifices formed as extensions of the helical groove of the rod within the head.

3. In a bit or auger, a body having an advance head with an unbroken periphery and a helical discharge groove extending from the rear of the head backwardly along the body, the advance end face of the head having a plurality of concentric helical extensions treminating in cutting shoulders at different longitudinal distances from the advance tip of the bit or anger, said head having passages from the shoulders to the discharge groove whereby the borings will be removed through the groove.

4. In a bit or auger, a body having independent concentric helical extensions upon its advance end face which extensions sions terminate in cutting shoulders at different distances from the advance tip of the bit or anger, the cutting edge of each of the shoulders extending transversely across its extension of the body substantially radially of the axis of the bit and along the outer side wall whereby each shoulder cuts a corner.

6. In a bit or auger, a body having concentric helical extensions upon its advance end face which extensions terminate in cutting shoulders at different distances from the advance tip of the bit or auger, the inner extension terminating in its cutting shoulder in advance of the outer extension, the body having a spiral chip conveying groove running endwise rearwardly from the extensions and communicating with the shoulders by individual passages.

In testimony whereof I have afiixed my signature in presence of two witnesses.

HENRI DOSIMONT.

Witnesses F. BREAUx, EM. GENARD. 

